1. Field of the Invention
The present invention relates generally to an apparatus and method for harvesting the seeds of native plant species, while maximizing the yield through an improved comb assembly design that includes a cam mechanism.
2. Description of the Related Art
Every year natural and man-caused disturbances (wildfire, construction of highways and facilities, mining, noxious weeds infestation, and overgrazing) damage and destroy millions of acres of native vegetation. These vast disturbances require restoration. Stewards of public lands, private landowners, and individuals and organizations concerned with environmental quality seek restoration of naturally occurring plant communities to provide forage, weed deterrence, water and nutrient management, wildlife habitat, and landscape stability.
Without restorative intervention, land recovery takes decades, leaving ecosystems vulnerable to erosion, invasive plant and insect species, and diseases. Long-term treatment plans call for reseeding native species, whose seed are often unavailable in the required quantities. Restoration is therefore constrained by limited supply and the high cost of the seed of native plant species. This unavailability of seed is frequently a direct result of seed characteristics that make it difficult to harvest sufficient quantities of viable seed. The present invention relates to a harvester that addresses the issue of difficult seed recovery by firmly removing ripe seeds from the seed heads of native plant species, while leaving unripe seeds.
The demand for novel and effective native seed harvesting equipment is directly linked to the increasing demand for difficult-to-harvest native seeds to be used in restoration of public and private lands. A principal reason for the limited availability of many species is that they do not lend themselves to conventional harvesting technologies. Many native plant species are only harvested by slow and inefficient hand collection, severely restricting supplies and increasing costs. Other species are subjected to traditional farm harvesting techniques that fail to maximize full harvest potential. There are currently four primary products and practices utilized in the harvest of native seeds, and they are discussed below.
A. Hand Harvesting
Hand harvesting can be as simple and inexpensive as having a cloth bag or pail for collecting seed, or it can involve use of a hand-held mechanical device. Hand harvesting achieves high seed recovery rates with good determination of ripe seed and may be the only feasible practice for very rough or sensitive terrain, wetlands, and small patches, but it is a slow and labor-intensive practice. For this reason, it is unsuitable for large-scale commercial production. The present invention is preferable to hand harvesting because it is much more productive and therefore much more commercially viable.
B. Direct Combining
Direct combining uses conventional harvest equipment. The combine cuts and threshes the plant to remove the seed and separate the seed from the other material that has been cut and collected. The seed is then conveyed into a hopper. The separated plant debris is deposited back onto the field. Combine equipment requires very precise adjustments, attachments and sometimes minor modifications to be suitable for a native seed crop. Because grass seed is similar in weight and structure to the chaff and other debris, some seed, especially immature seed, is not separated from the debris and is lost. Combines may also be used in combination with a stripper header. Stripper headers are not suitable for harvesting light native seeds and are only useful for heavy-seeded grains such as high-yield wheat, soybeans and rice. The prices of seed that can be easily harvested by combines (e.g., the wheatgrass and the wild ryes) are generally lower than the prices of other types of native seed because the seed that can be easily harvested by combines is more commonly available. The present invention is preferable over direct combining because it can successfully harvest the less common and more expensive native seed species that direct combining cannot effectively harvest.
Direct combining results in the harvest of seed of unwanted species and the commingling of that seed with the desired seed (i.e., contamination). Direct combining also results in the harvest of seed that has not ripened. Species that have indeterminate ripening processes are poor candidates for traditional combining because both ripe and immature seed is harvested. The immature seed is still in the process of filling and ripening, which reduces the vigor and even the viability of the immature seed, thereby wasting much of the potential seed crop. By virtue of the design of the present invention, it firmly removes ripe seed and leaves unripe seed undamaged to mature. A combine is not appropriate for sensitive environments or in small-sized and rough terrain, whereas the present invention is effective in those environments.
C. Combining Preceded by Windrowing
In windrowing, the native seed stalks are cut and left in the field to mature. After a number of days appropriate to the seed species, a combine with a pickup attachment collects and threshes the seed. This method is suitable for the portion of seed of indeterminate species that has matured enough that it can continue to fill and mature in the windrow for days after cutting, and it protects most of the seeds with a high tendency for shattering by virtue of the physical protection afforded by the windrow. The seed has a lower moisture content by the time threshing is completed, which lessens the need to further dry the seed.
While the grasses remain in windrows, however, the seed harvest is still somewhat vulnerable to damage by rain and wind. This method is not suitable for short grasses because of the difficulty of retrieving the swathed stalks. The windrowing must be followed by a combine with a swath pickup device to collect the swath of cut plants from the ground and to separate the seeds, which makes the windrowing method subject to some of the same contamination and separation problems as direct combining. The present invention is preferable to windrowing because it immediately collects mature seed with no possibility of shattering, leaves immature seed undamaged so it can fill and increase in vigor and mature to become more viable, and it also addresses the contamination and separation deficiencies involved with the use of the combine.
D. Stripping
Stripping involves removing the mature seed from the seed head while in the field, leaving the plant intact. Strippers to date have mostly involved rapidly rotating brushes or stationary combs. Simple brush strippers are used mostly with seeds that are lightweight and that have long awns or protuberances. All of the commercial brush strippers include a rotating brush with air inflow that pulls the seed into a collection chamber, but the treatment applied is highly uneven among plants. This results in as little as half or less of potential seed being recovered. Because the plant is not destroyed, seed recovery is increased by a second or even a third harvest on grasses that do not mature in a uniform fashion, for a higher yield than with single-pass harvesting (as in windrowing and combining). Commercially available strippers are loaded on the front end of, or are pulled behind, conventional farm equipment. Stripping can be particularly beneficial to crops that do not tolerate continual clipping of the growth tips as a combine or windrower does.
Strippers with only combs and no brushes are less expensive than brush strippers, but the percentage of seed recovered is often even lower than with the rotating brush strippers. Both types of currently used strippers have the disadvantage of not positively engaging the seed heads to remove the seed from the seed head. An added disadvantage is that they require the added time and labor costs of repeat passes over unevenly maturing fields. Both brush and comb strippers perform better than combining in addressing contamination and separation issues, however.
The present invention is an integrated brush and comb stripper that substantially increases the percentage of seed recovered by positively engaging the seed heads and delivering a controlled brush treatment to remove, capture and convey all mature seed to a hopper. The reason the harvest efficiency of brush strippers is not as high is because the stripper design relies solely on the brush action to dislodge the seed, which tends to cause some plant types to lean, be blown or be nudged away by the brush itself. Heavier seeds or improperly positioned seeds fall to the ground before the airflow vacuum can pull them into the hopper.
The present invention solves these problems by combining a brush with a comb assembly to maximize seed recovery, by providing for adjustment of the distance between the counter-rotating brushes and combs to maximize the yield for a particular species, by providing a uniform brushing treatment to all seed heads as they pass through a zone of evenly controlled brush treatment, by having seed dislodgement take place within the vacuum airflow, and by separately controlling the speed of the brush and the combs. By virtue of a unique cam design, the zone of controlled brushing is increased from a single point of contact to a controlled length of comb rotation. The use of the cam mechanism further increases yield and permits fine-tuned adjustments to provide the same treatment to all seed heads.